This invention relates to the removal of particles or contaminants from a fluid stream, and more particularly, to the cyclonic inertial separation of particles from a main fluid stream.
Cyclonic inertial fluid cleaners or separators are known. Typically, a static generator, with straight or helical vanes, is located within a housing to impart a spin on the main fluid stream. The spin displaces particles in the main fluid stream radially outward. The main fluid stream then enters an outlet tube, with particles ideally traveling near the perimeter of the inner diameter of the housing and then traveling through a scavenge port.
Only the largest particles, however, have enough centrifugal force to stay near the perimeter of the inner diameter of the housing. If their centrifugal force is greater than their flow (radial inward) force at the entrance of the outlet tube, particles make it to the scavenge port. Thus, the radial inward velocities of the particles must be reduced to achieve sufficient separation or cleaning.
In addition, the non-uniform velocity profiles and high (radial inward) peak velocities result in inefficiencies and high pressure drops, which can lead to higher costs to replace the lost energy. In addition, safety risks can also result as particle-laden fluid streams traveling at high velocities wear down equipment, such as bearings and the like. Such cleaners can be enlarged in size to reduce velocities, but that can also increase costs and inefficiencies.
Accordingly, there is a need for a cyclonic inertial fluid cleaner that ensures more uniform velocity profiles and decreased velocities. A reduction in (radial inward) velocity enables the cleaner to achieve greater efficiencies and lower pressure drops. Moreover, there is a need for a cost-effective process that optimizes space and reduces safety risks.
The present invention provides an apparatus for cyclonic inertial fluid cleaning. In particular, an apparatus for separating particles from a fluid stream is provided that includes a housing, a generator, and an outlet tube. The housing has an entrance, a rear portion, a scavenge port, and at least one inner wall to define a space. The outlet tube is disposed within the space and has an inlet, an outlet, an upstream end, a downstream end, an inner diameter and an outer diameter. The generator has vanes disposed within the space between the housing entrance and the outlet tube inlet.
The apparatus of the present invention improves on the cleaners of the prior art by providing an outlet tube that has a plurality of slots disposed about its outer diameter. Consequently, the fluid stream flows from the housing entrance through the generator and toward the rear portion so that the fluid stream exiting the outlet tube is free of a substantial portion of the particles present in the fluid stream at the housing entrance. In addition, a substantial portion of the particles present in the fluid stream at the housing entrance exit the scavenge port. Accordingly, the apparatus of the present invention provides an apparatus that is effective in removing a substantial portion of the particles entering the housing entrance without creating an undesirable pressure drop.
In one aspect of the invention, a second plurality of slots is disposed about the outer diameter of the outlet tube and located between the downstream end and the first plurality of slots.
In another aspect of the invention, a third plurality of slots is disposed about the outer diameter of the outlet tube and located between the downstream end and the second plurality of slots.
In yet another aspect of the invention, the generator has vanes that are helical and tapered at an angle.
These and other features of the invention will become apparent upon review of the following detailed description of the presently preferred embodiments of the invention, taken into conjunction with the appended figures.